1. Field of the Invention
The field of the invention relates to support stand apparatus and more particularly to a Christmas tree stand with a new and improved clamping mechanism to accommodate and securely hold tree trunks in a wide range of diameters.
2. Description of the Prior Art
A wide variety of Christmas tree stands have been developed and appear in the patent literature. Most of these are of the type which comprises a water-holding receptacle to receive the tree trunk, from the base of which radially extend a plurality (three or four) of stabilizing feet. Near the opening of the receptacle there is provided a cover, collar or a cylindrical neck associated with gripping means to clamp the trunk and maintain the tree in a vertical position.
The greatest variation among Christmas tree stands of this general type-and the source of most practical difficulties-resides in the structure of the gripping means.
In many such Christmas tree stands, metal screws or clamps are provided to hold the tree trunk in the stand as in U.S. Pat. Nos. 2,630,994 and 4,571,881. The tendency of the end of the screws to pierce the trunk, negatively affecting the stability of gripping engagement, has been sought to be addressed in some devices by equipping the screw ends with arcuate clamping plates or other contoured gripping members as, for example, in U.S. Pat. Nos. 4,825,586 and 5,725,193. Nevertheless, such devices are often subject to insecure gripping action by reason of the limited surface area over which force is applied to the tree trunk by threaded members. There is the further disadvantage with threaded members for the threads to back off and loosen the clamping or, particularly with metal screws, to seize up making it difficult and inconvenient to release the gripping engagement with the tree trunk.
In other such tree stands, the gripping of the tree trunk is effected or augmented by insertion between the holder and the trunk of wedge-shaped gripper inserts. Examples are provided by U.S. Pat. Nos. 2,701,699; 4,261,138; and 5,497,972. If undesired migration of the wedge inserts from their gripping position is to be reliably prevented, however, a locking mechanism is generally required, adding to the complexity and cost of construction of the tree stand.
It is a primary object of the present invention to provide a Christmas tree stand with a novel clamping mechanism which is simple to erect and disassemble and easy to use.
It is a further object of the invention to provide a Christmas tree stand which can accommodate a wide range of tree diameters and exert a constricting force on the tree trunk without the aforementioned disadvantages of common screw systems.
It is a still further object of the invention to provide a disassemblable Christmas tree stand in which all components are made of injection moulded thermoplastic materials, which will not rust in use or mark up the surface on which the stand is erected.